Britney Spears had a fling with whom?

Britney Spears announces her new show at Planet Hollywood Vegas on Tuesday, Sept. 17, 2013 in Las Vegas. (Al Powers/Invision/AP)

Robin Thicke had a fling with a former child star who grew up to become quite the sex bomb.

No ... not the twerker.

In Touch magazine reported that Thicke had a thing with Britney Spears 10 years ago, when she was rebounding from Justin Timberlake.

“The pair had a fling in 2003, when Britney was at the top of her game and Robin was trying to get recognized,” a source reportedly told the magazine. “He was trying hard to develop a reputation as a hot, young singer, and (Britney) was the biggest thing in show business.”

The pair met while collaborating on a project that was never released and “started hooking up,” the source said.

How did we go a whole decade without knowing this? They must have been meeting up at Andy Kaufman's house.

Maybe it was Thicke who sent Spears off the rails. Because it wasn't long afterward, in January 2004, that Spears' free-fall of looniness began when she went to Las Vegas and married her old pal Jason Alexander. Not that Jason Alexander.

In Touch reported Thicke continued his long-term relationship with high school sweetheart Paula Patton. Thicke's reps are denying the whole thing.